Electrical signaling.



A. PESSENDEN.

ELECTRICAL SIGNALING,

APPLICATION FILEB DBG.Z3,1907.

Patented Dec. 2G, 1919.

IN VEN TOR.

. UNITE-D STATES rieI ENT oEErCE.

REGINALD A. EESSENDEN, or BRANT ROCK, MASSACHUSETTS,

ELECTRICAL SIGNALING.

-l "'i'T alljwhqm iii 'may coi'weiat: 'Be 1t lrnown that'I. REmALn A.Fressennum, a citizen of the United States, residlng at- Brant Koeln/inthe county o f Plymouth',

State of- Massachusetts, liaye'ini-'ented ce'rtain new and usefulImprovementsin Elecvtrical Signaling, of which improvements thefollowing is a Specification;

My invention relates to i paratus for reld, ceivfng. electric signalsand) more particu'- larlyv to means"foriani1 ifying the strength ofreceived signals-.f

.In the accompanying drawings forming a f partof this specification tlefigure 'shows au arrangement of the apparatus Suitable for carrying outthe invention.

The invention herein described 'has forits object the moreetiicient'receipt fof electric signals andthe amplification of receivedsignals and-the elimination of disturbing,r linfluences. i .l

In the practice of my invention I employ Sinle wire DArsonvalgalvanome'ter of meeting of 1894 and illustrated in U. S. Patent 706,737Figure 2, and cause this galvanometer' to alter the'rcsistance of alocal circuit.'

In the figure, 1 is an electro-magnet shown for conveniencediagrammatically, but in practice having its pole pieces extending overthe greater' part o'f the conducting filament 2, 2', so that thisfilament is in an intense magnetic field. To the middle of the filamentis attached 'a Somewhat thicker ivireof aluminum 3, for the doublepurpose' of gvinga wider shadow and of makingthe 'filament' vibrate ata. more definite rate.

40 The lovver end ofthe filament iS attached to'J va small lever 4;vcarrying a small'- piece o f iron 5 and s o arranged that by adjustingthe sliding contact 6 of the resistance 7 and so altering the currentfrom the local 'battery i5 8, and theistiength of the magnet 9, thefila- Ament is ut under more or less tension -and thereby lts naturalfrequency of vibration is adjusted: A

The filament and the lever referred to are inclosed in a glass tube 10,10 from which Specification of Letters 1 Application filed December 23,1907,

thegtype described by Vme at the American ociation for theAdvancement ofScience iatented'neefzo, 191e;

eadsai'roii'set tube' 1l s o that'the air in the,Av gass tube 10, 10 maybeppmped out.

' 12 is a moderately-.thick 'xvire'of platinum' iridium or the filamentof. a Nernst lamp, excited by the dynamo l3'and regulated byivf)1 theadjustable resistance 14.

15 and 16 are cylindrical lenses, for focusing the lradiant heatproduced by tthe heated filament '12 on the bolometer wire 17, invilch awaythat ivhenthe 'wire 3 isin its norma-l 60 position the bolometer wire17 vis in its Shadow, but when the Wire 3 is. shifted to lone side theradiant heat falls ori-the bolomon the bolometer wire 17 and changes itsresistance, thereby actuating the sensitive re'- lay 2O and pfoduclnfrair indication.

The natural )erio of the filament 10, 10 is preferably ad ableresistance 7 so that it is identical with that of the received impulses.1

Having` thus described 'in v. invention and illustrated its use, whatIclaim as new and. desire to secure by Letters Patent is the following:v

1.111 al system of'signaling. a galva'pometer, adapted to produce amotion on. receipt of-the signals 4to be detected, a sourceof radiantheat, a bolometer circuit, and means for focusing' the radiantlieatso tl1at',=t;l1e movement of the galvanometerdetermines the amount of saidradiant heat falling on the bolometer.

2. In apparatus vfor signaling, the combi-4 95;v nation of agalvanometer adapted to pro# `f duce a motion" on receipt of the'signals to be detected, a Source of radlant heat, a

bolometer circuitcom prising a Wire'whose Y resistance alters on beingexposed to radlant 1Q justed by means oi the varie., '3o

heat so that theshndow 0i thc movmg mrt'. i stl'mfr a 'nonouncednatural' )erlocl of vlbrug hun, :mgl clectromagncilcmenus foradjustpt-bf th signals to g -lnggj szml mllnrzll p'cnod of#ubratlol-l.'A.15 f {rl tstm'mny whereof I hnvc hereunder sxgngd -mv name mthepresence, of the s ub-

